A court-bouillon is a simple stock, or as Larousse Gastronomique puts it a “spiced aromatic liquor”, mostly used for poaching fish and crustacea, though other white meats such as chicken and veal can be poached in it too, as can vegetables or certain cuts of offal. “Spiced” isn’t really the best word for it, as it contains vegetables and herbs, the only spice being black peppercorns.

Fish can be poached on the stove top in this way, or in the oven, and the key is to try to achieve a cooking temperature of around 160℃ or 170℃. For the fish I poached this week, I prepared the court-bouillon (it means ‘short broth’) in a pot on the hob, then left it to cool, then strained it into my clay pot and cooked it in my gas oven, set to 170℃, for about an hour (but some of that time was taken by the stock coming up to the requisite heat).

I first wrote about my beautiful terracotta clay pot here and it came to mind when planning to poach a whole (fairly small) cob in a court-bouillon, though it did mean trimming the tail and head of the fish, which was a pity, as it would have looked great had they been on, for presentation purposes.

The ingredients in a court-bouillon can vary greatly, although the core ingredients of a more or less traditional one would include onion, celery, carrot, leek, parsley, and peppercorns, or at least some of those ingredients. It should be salted too (that’s where the necessary saltiness of the fish cooked in it will come from), and variations can include white wine (a fruity but dry variety is recommended by Larousse), or milk, or lemon or vinegar, or simply “eau de sel”, which Larousse calls “the easiest kind of court-bouillon to prepare as it consists only of salted boiling water”. That’s too spartan for my liking (I am only ever in search of flavour in my cooking); Larousse observes that it usually has no flavour other than salt, “but a little thyme and a bay leaf may be added if desired”.

But you can adapt any or all of this to your own palate and imagination; it’s a poaching stock and will take on whatever flavour you put into it. (Fancy a sesame flavour for your fish? Nothing’s stopping you, although with every bite you eat, a French chef somewhere will die).

My recipe, as you’ll see, includes a halved lime, if only because I found myself out of lemons. But if you think about it, what harm can a little lime do in a stock for poaching fish, other than to annoy the most intransigent of French chefs for whom Larousse is the Bible and to be obeyed? Cooking would be no fun if every last “rule” was never toyed with like a kitten with a shoelace.

There are some rules that do need to be adhered to, however. The stock needs to be cooled before immersing the fresh (cleaned and scaled, obviously) fish in it, and the court-bouillon should be sufficient to entirely cover the fish. The vessel needs a lid, as this is all about poaching, which means immersion, so you do not want your poaching liquor to evaporate leaving part of the fish beached, as it were. The heat must be gentle (so 160℃ is perhaps safer than 170℃), or you can poach it on the stove top in a fish kettle but on a very low heat, just the gentlest simmer (it is likely to cook quicker on the stove top). (Do people still have fish kettles?) Whatever dish you use, the fish should fish quite snugly.

The sort of people that use temperature gadgets might like to know that fish is ready at an internal temperature of 140℃. I wouldn’t want to jab a thermometer into the delicate flesh of a fish and risk tearing it; and rupturing it is not what you want. So please tread carefully if doing so.

How long to cook it? Larousse advises 25 minutes for fish that is 5 cm thick and an hour if it’s 13 cm thick. This will mean the thickest part of the fish at its broadest circumference. I would take into account that the fish (if using something similar to my clay pot) is going into a cold oven at room temperature (you’ve cooled the court-bouillon down, remember), so a good 20+ minutes of that cooking time is going to be devoted to the stock reaching its cooking temperature. A clay pot such as mine, or a Romertopf, has to go into a cold oven, after first being soaked for half an hour in cold water and drained.

Ingredients

1 medium kob (aka kabeljou, daga, drum, daga salmon) or other firm white fish

1 large carrot, diced

1 large celery stick, sliced thinly

1 large or 2 small leeks, sliced thinly

1 small onion, diced

4 or 5 parsley sprigs

1 tsp black peppercorns

½ a lemon or 1 lime, in 2 halves

1.5 litres cold water

Salt, about 1 Tbsp (scant, not heaped), but add a little at a time and taste to be sure you don’t oversalt it

Method

The fish in the pot before being poached. Note how completely submerged it is in the court-bouillon. (Photo: Tony Jackman)

Ask your fishmonger to clean and scale the fish for you. Either cook it head and tail on (if your poaching dish is long enough) or remove the tail and head and discard or freeze for use in a fish stock.

Note that you must not preheat the oven if you’re using a clay pot, but if it’s a metal or other oven-proof dish, preheat it to 160℃ or 170℃ (depending on how well you know your oven; my gas oven needed 170℃, but an electric one might be best set to 160℃).

First make the court-bouillon:

Pour the water into a heavy bottomed pot and add the prepared carrot, onion, leeks, celery, lemon (or lime), and peppercorns. If you like, add a sprig or two of thyme and use less parsley. Salt it a little at a time, tasting, until the level of saltiness is just right. There is no other reliable way to do this; you need to assess it by taste. The fish will poach in this stock and will take on the level of saltiness. So the power of the salt is in your hands.

Bring the pot to the boil, then reduce it to a moderate simmer, and cook it for about 45 minutes. Turn the heat off and leave it to cool to room temperature.

If using a clay pot, as I did, soak it in cold water for 30 minutes, drain and dry it.

Rinse the fish and pat it dry. Remove the head and tail if necessary for fitting into the pot, but leaving them on is fine. Leave the skin on (but not scales).

Strain the court-bouillon through a fine sieve into a large jug.

Place the fish in the pot/dish and pour the court-bouillon over it, making sure that the entire fish is submerged in the stock.

Put the lid on and place it in a cold oven.

Turn the heat to 160℃ or 170℃ and close the door.

The cooking time may vary depending on your oven. Bear in mind that the fish will not start to poach until the stock inside it has reached a temperature of around 160℃, so factor that in. In my case, the fish was in the gas oven for a full hour, but do judge it by what you know about your oven’s habits. As I always say, no two ovens are quite alike.

Fluffy mashed potato, well salted and finished with lots of butter stirred into it, makes a perfect accompaniment. I also made a sauce by pouring off about 500 ml of the court-bouillon (after the fish was cooked) into a pot and reducing it. There’ll be no need to salt it. Finish it with a good splash of fresh cream, simmer it down, add a splash of liquor (I used Pierre Jourdan Ratafia, but a sherry or citrus liqueur would work well), reduce gently for it to thicken, and serve with the fish. DM/TGIFood

Tony Jackman is Galliova Food Champion 2021. His book, foodSTUFF, is available in the DM Shop. Buy it here. 

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